Attention BIOL 207 Students

Hello

So – two of you have written to me over the past week and told me that you couldn’t access the anthropogenic biomes link. I’m not sure why there was a problem. Here is the link again –> http://www.eoearth.org/article/Anthropogenic_biomes. Yes, this material is fair game for the exam tomorrow.

Okay – another student emailed me to tell me that s/he has still not been able to open the link. very odd. here’s the information from the link:

Table of Contents

Introduction

Cropland mosaic near Pokhara, Nepal, 1999.

Anthropogenic biomes describe globally-significant ecological patterns within the terrestrial biosphere caused by sustained direct human interaction with ecosystems, including agriculture, urbanization, forestry and other land uses. Conventional biomes, such as tropical rainforests or grasslands, are based on global vegetation patterns related to climate. Now that humans have fundamentally altered global patterns of ecosystem form, process, and biodiversity, anthropogenic biomes provide a contemporary view of the terrestrial biosphere in its human-altered form. Anthropogenic biomes may also be termed “anthromes” to distinguish them from conventional biome systems, or “human biomes” (a simpler but less precise term).

Humans and ecosystems

Humans are the ultimate ecosystem engineers, routinely reshaping ecosystem form and process using tools and technologies, such as fire, that are beyond the capacity of any other organism. This exceptional capacity for ecosystem engineering, expressed in the form of agriculture, forestry, industry and other activities, has helped to sustain unprecedented population growth, such that humans now consume about one third of all terrestrial net primary production, move more earth and produce more reactive nitrogen than all other terrestrial processes combined, and are causing global extinctions and changes in climate that are comparable to any observed in the natural record. Clearly, humans are now a force of nature rivaling climate and geology in shaping the terrestrial biosphere and its processes. As a result, the vegetation forms predicted by conventional biome systems are now rarely observed across large areas of Earth’s land surface.

Anthropogenic biomes: a global view

Viewing a global map of anthropogenic biomes shows clearly the inextricable intermingling of human and natural systems almost everywhere on Earth’s terrestrial surface, demonstrating that interactions between these systems can no longer be avoided in any significant way.

Recent analyses[1] have demonstrated that more than three quarters of Earth’s land surface has been reshaped by human activity. Less than a quarter of Earth’s ice-free land is wild, and only 20% of this is forests; >36% is barren, such that Earth’s remaining wildlands account for only about 10% of global net primary production. More than 80% of all people live in the densely populated urban and village biomes that cover approximately 8% of global ice-free land. Agricultural villages are the most extensive of all densely populated biomes; one in four people lives within them.

Anthropogenic biomes are not simple vegetation categories, and are best characterized as heterogeneous landscape mosaics combining a variety of different land uses and land covers. Urban areas are embedded within agricultural land, trees are interspersed with croplands and housing, and managed vegetation is mixed with semi-natural vegetation (e.g. croplands are embedded within rangelands and forests). For example, Croplands biomes are mostly mosaics of cultivated land mixed with trees and pastures, and therefore possess just slightly more than half of the world’s total crop-covered area (8 of 15 million km2), with most of the remaining cultivated area found in Village (~25%) and Rangeland (~15%) biomes. While Forested biomes are host to a greater extent of Earth’s tree-covered land, about a quarter of Earth’s tree cover was found in Croplands biomes, a greater extent than that found in Wild forests (~20%).

Education and Research

Map of Anthropogenic Biomes.

Biomes are fundamental units of the biosphere and are found in almost every introductory biology and earth science textbook. While not a replacement for existing biome systems based on vegetation and climate, anthropogenic biomes offer a new view of the terrestrial biosphere based on the irreversible coupling of human and ecological systems at global scales. This new model of the biosphere moves us away from an outdated view of the world as “natural ecosystems with humans disturbing them” and towards a vision of “human systems with natural ecosystems embedded within them”. This is a major change in perspective but it is critical for sustainable management of our biosphere in the 21st century.

Sustainable ecosystem management must develop and maintain beneficial interactions between managed and natural systems: avoiding these interactions is no longer a practical strategy. Though still at an early stage of development, anthropogenic biomes offer a framework for incorporating humans directly into models and investigations of the terrestrial biosphere and its changes, providing an essential foundation for ecological research in the 21st century.